Cardiac troponin I serum concentrations in newborns: A study and review of the literature

Background: Serum cardiac troponin I (cTnI) is a specific marker of cardiac injury. The use of cTnI in neonates, especially in relation to perinatal asphyxia has not been extensively examined. We defined the range of normal values of cTnI in newborns, and study factors that may influence these concentrations. Methods: Serum cTnI concentrations were measured on the third day of life in 179 normal newborns: 157 were term (after 37 weeks, mean: 39.7 +/- 1.1, range: 37-42) and 22 were premature infants (mean: 32.6 +/- 2.9, range: 27-36 weeks). Results: Mean cTnI for the term infants was 0.63 +/- 0.58 ng/ml (median: 0.50, range: 0.00-4.30). The concentration of 1.80 ng/ml, can serve as the upper limit of normal values. There was a borderline significant trend for higher cTnI in preterm infants. The number of newborns with cTnI > 1.80 ng/ml was significantly higher after delivery by caesarean section, compared to vaginal delivery (14.6% vs. 2.9%,p < 0.02). No other significant associations were found between cTnI and perinatal or neonatal parameters. Conclusions: Normal reference values for cTnI in healthy term newborns were defined, but need to be addressed with caution due to the wide range of normal values. 0 2006 Elsevier B.V. All rights reserved.